Vehicle suspension damper

ABSTRACT

A vehicle suspension damper for providing a variable damping rate. The vehicle suspension damper comprises a first damping mechanism having a variable first threshold pressure, a second damping mechanism having a second threshold pressure, and a compressible chamber in communication with a damping fluid chamber, wherein the second damping mechanism is responsive to a compression of said compressible chamber.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and is a continuation of the patentapplication Ser. No. 16/287,860, entitled “VEHICLE SUSPENSION DAMPER,”with filing date Feb. 27, 2019, by Joshua Benjamin et al., which isincorporated herein, in its entirety, by reference.

The application with Ser. No. 16/287,860 claims priority to and is acontinuation of the patent application Ser. No. 15/631,655, now issuedU.S. Pat. No. 10,221,914, entitled “VEHICLE SUSPENSION DAMPER,” withfiling date Jun. 23, 2017, by Joshua Benjamin et al., which isincorporated herein, in its entirety, by reference.

The application with Ser. No. 15/631,655 claims priority to and is acontinuation of the patent application Ser. No. 14/931,259, now issuedU.S. Pat. No. 9,688,347, entitled “VEHICLE SUSPENSION DAMPER,” withfiling date Nov. 3, 2015, by Joshua Benjamin et al., which isincorporated herein, in its entirety, by reference.

The application with Ser. No. 14/931,259 claims priority to and is acontinuation of the patent application Ser. No. 14/502,679 and nowissued U.S. Pat. No. 9,188,188, entitled “VEHICLE SUSPENSION DAMPER,”with filing date Sep. 30, 2014, by Joshua Benjamin Yablon et al., whichis incorporated herein, in its entirety, by reference.

The application with Ser. No. 14/502,679 claims priority to and is acontinuation of the patent application Ser. No. 12/509,258 and nowissued U.S. Pat. No. 8,869,959, entitled “VEHICLE SUSPENSION DAMPER,”with filing date Jul. 24, 2009, by Joshua Benjamin Yablon et al., whichis incorporated herein, in its entirety, by reference.

The application with Ser. No. 12/509,258 claims priority to the patentapplication Ser. No. 61/227,775, entitled “VEHICLE SUSPENSION DAMPER,”with filing date Jul. 22, 2009, by Joshua Benjamin Yablon., which isincorporated herein, in its entirety, by reference.

The application with Ser. No. 12/509,258 is a continuation-in-part andclaims priority to the patent application Ser. No. 12/407,610 and nowissued U.S. Pat. No. 8,894,050, entitled “METHODS AND APPARATUS FORSUSPENDING VEHICLES,” with filing date Mar. 19, 2009, by Dennis K.Wootten et al., which is incorporated herein, in its entirety, byreference.

The application with Ser. No. 12/509,258 claims priority to the patentapplication Ser. No. 61/157,541, entitled “Methods and Apparatus forCombined Variable Damping and Variable Spring Rate Suspension,” withfiling date Mar. 4, 2009, by Dennis K. Wootten et al., which isincorporated herein, in its entirety, by reference.

The application with Ser. No. 12/509,258 claims priority to the patentapplication Ser. No. 61/083,478, entitled “METHODS AND APPARATUS FORVARIABLE DAMPING SUSPENSION” with filing date Jul. 24, 2008, by JoshuaBenjamin Yablon., which is incorporated herein, in its entirety, byreference.

CROSS REFERENCE TO RELATED U.S. APPLICATIONS

This Application is related to U.S. patent application Ser. No.14/271,091, now issued U.S. Pat. No. 9,186,950, entitled “METHODS ANDAPPARATUS FOR COMBINED VARIABLE DAMPING AND VARIABLE SPRING RATESUSPENSION”, by Dennis K. Wootten et al, assigned to the assignee of thepresent invention, filed May 6, 2014.

This Application is related to U.S. patent application Ser. No.13/005,474 and now issued U.S. Pat. No. 9,156,325, entitled “METHODS ANDAPPARATUS FOR VEHICLE SUSPENSION HAVING MULTIPLE GAS VOLUMES”, by MarioGalasso et al, assigned to the assignee of the present invention, filedJan. 12, 2011.

This Application is related to U.S. patent application Ser. No.12/717,867, now abandoned, entitled “METHODS AND APPARATUS FOR COMBINEDVARIABLE DAMPING AND VARIABLE SPRING RATE SUSPENSION”, by Dennis K.Wootten et al, assigned to the assignee of the present invention, filedMar. 4, 2010.

All references cited in the specification, and their references, areincorporated by reference herein in their entirety where appropriate forteachings of additional or alternative details, features and/ortechnical background.

US GOVERNMENT RIGHTS

Not applicable.

FIELD

Embodiments of the present technology relate generally to the field ofvehicle suspension.

BACKGROUND

Vehicles, including wheeled vehicles, are typically suspended to absorbshock encountered while traversing uneven terrain. Wheeled vehiclesusually include one suspension assembly per wheel so that each wheel mayabsorb shock independently. In many cases each such suspension assemblycomprises both a spring portion and a damping portion. The springportion may consist of a mechanical spring, such as a wound helicalspring, or it may comprise a pressurized volume of gas. Gas is oftenused because it is light weight. Unlike typical simple mechanicalsprings, gas springs have non-linear spring rates. Compound mechanicalsprings may also have non-linear rates. A single gas spring has a springrate that becomes highly exponential at compression ratios greater thanabout sixty percent. As a practical matter that can mean that a shockabsorber including a gas spring can becomes very stiff just past themiddle of its compressive stroke. Such excess stiffness over an extendedlength of the stroke is often undesirable (e.g. harsh riding vehicle).

In performing the dampening function, the damping mechanism of a shockabsorber also creates resistance of the shock absorber to movement (e.g.compression and/or rebound). Unlike the spring which resists based oncompressive displacement, fluid dampers usually have resistance tomovement that varies with displacement rate (i.e. velocity). That may bedisadvantageous because low velocity (i.e. low frequency) high amplitudeshocks may compress the spring while the damper offers littleresistance. In such cases the shock absorber may compress beyond adesired point because the damper did not contribute to shock compressionresistance.

What is needed is a shock absorber dampener that offers resistance tomovement as a function of axial displacement. What is needed is asuspension dampener that is relatively compliant at low axialdisplacement and progressively more resistant to movement at higherdisplacements. What is needed is a suspension (e.g. shock absorber,fork) having a gas spring with good low displacement resistance and morecompliance at greater compression ratios. What is needed is a shockabsorber having a gas spring and a dampener that can be tuned togetherto yield optimized shock absorber force/travel/velocity characteristics.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings, which are incorporated in and form a part ofthis specification, illustrate embodiments of the present technology foran axle for removably retaining a wheel on a vehicle, and, together withthe description, serve to explain principles discussed below:

FIG. 1 is a cross-sectional view of a bicycle shock absorber embodimentas disclosed herein.

FIG. 2 is a cross-sectional view of a valve piston embodiment asdisclosed herein.

FIG. 3 is a cross-sectional view of a valve piston embodiment asdisclosed herein.

FIG. 4A-E are a cross-sectional view of a valve piston embodiment asdisclosed herein.

FIG. 5 is a cross-sectional view of a valve piston embodiment asdisclosed herein.

FIG. 6 is a cross-sectional view of a valve piston embodiment asdisclosed herein.

FIG. 7 is a cross-sectional view of a valve piston embodiment asdisclosed herein.

FIG. 8A is a cross-sectional view of a fork damping cartridge embodimentas disclosed herein.

FIG. 8B is a cross-sectional view of a two legged vehicle (e.g. bicycle)fork comprising a vehicle suspension damper embodiment as disclosedherein.

FIG. 8C is a cross-sectional view of a vehicle suspension damper andrelated components within a leg of a two legged fork embodiment asdisclosed herein.

FIG. 8D is a cross-sectional view of a two legged vehicle (e.g. bicycle)fork comprising a vehicle suspension damper embodiment as disclosedherein.

FIG. 8E is a blown up view of the cross-sectional view of FIG. 8D of atwo legged vehicle (e.g. bicycle) fork comprising a vehicle suspensiondamper embodiment as disclosed herein

FIG. 8F is a blown up view of the cross-sectional view of FIG. 8E of atwo legged vehicle (e.g. bicycle) fork comprising a vehicle suspensiondamper embodiment as disclosed herein

FIG. 8G are cross sectional views of a vehicle suspension damper andrelated components within a fork 852 configured for a motorcycle.

FIG. 8H is a cross sectional view of components within a base valveassembly embodiment as disclosed herein.

FIG. 8I is a cross sectional view of components within a base valveassembly embodiment as disclosed herein.

FIG. 8J is a cross sectional view of components within a base valveassembly embodiment as disclosed herein.

FIG. 9 is a flow chart of an example method for altering a damping rateof a vehicle suspension damper.

FIG. 10 is a blown-up schematic of an example eyelet assembly embodimentas disclosed herein.

FIG. 11A and FIG. 11B are schematics of an example cam embodiment asdisclosed herein.

FIG. 12A-D are schematics of different views of an example RD adjustknob embodiment as disclosed herein.

FIG. 13 is a cut away view of a shock absorber embodiment as disclosedherein.

FIG. 14A shows a pressure regulator device having unequal opposingpiston areas wherein the piston areas share a common differential datum(e.g. ambient air) as disclosed herein.

FIG. 14B shows a pressure regulator device having unequal opposingpiston areas wherein the piston areas share a common differential datum(e.g. ambient air) as disclosed herein.

FIG. 15 is a cut away view of an upper tank portion of a shock absorberembodiment and shows the details of a fill valve assembly as disclosedherein.

FIG. 16 shows a modular fill valve assembly embodiment as disclosedherein.

DESCRIPTION OF EMBODIMENTS

One embodiment hereof comprises a gas spring shock absorber for avehicle. In one embodiment the vehicle is a bicycle. The shock absorberis advantageous because it includes a damper having a manuallyadjustable damping resistance and a position and/or pressure sensitivevariable damping resistance. The manually adjustable damping functionallows a user to adjust a “platform” threshold which must be exceededbefore the shock absorber can experience significant compression travel.It allows the user to establish a level, in one embodiment, forcompression damping whereby such damping is increased or decreasedselectively. A bicycle rider for example may choose to set a fairly highthreshold for the function of compression damping (by adjusting andincreasing the seating force of damping adjustment valve 204 in aperture206, for example, as discussed below) thereby reducing pedal inducedsuspension bob. In one embodiment the manual adjustment and the positionsensitive variability of the damping are independent. In one embodimentboth chambers of a dual gas chamber gas spring can be filled simply inone pressurization step. In one embodiment a gas chamber shock canfurther include an internal floating piston and at least a second gaschamber exerting a base operating pressure on the damping fluid. In oneembodiment the suspension is a bicycle or motorcycle fork. Optionallydamping fluid can be isolated from the gas spring.

U.S. Pat. No. 6,135,434, which patent is herein incorporated byreference in its entirety, shows certain variations of positive andnegative spring mechanisms. Another selectively variable dampingmechanism is shown in U.S. Pat. No. 6,360,857 which patent is hereinincorporated by reference in its entirety. Other selectively variabledamping mechanisms are shown in U.S. patent application Ser. Nos.11/567,074 and 11/617,713 each of which is herein incorporated byreference in its entirety. Optionally, any of the foregoing mechanismsmay be integrated, or used in combination, with any other featuresdisclosed herein.

U.S. Pat. Nos. 6,415,895, 6,296,092, 6,978,872 and 7,308,976, each ofwhich patents is herein incorporated by reference in its entirety, showcertain variations of position sensitive damping mechanisms. Anotherposition sensitive damping mechanism is shown in U.S. Pat. No. 7,374,028which patent is herein incorporated by reference in its entirety.Another position sensitive damping mechanism is shown in U.S. Pat. No.5,190,126 which patent is herein incorporated by reference in itsentirety. Optionally, any of the foregoing mechanisms may be integrated,or used in combination, with any other features disclosed herein.

U.S. Pat. Nos. 6,581,948, 7,273,137, 7,261,194, 7,128,192, and6,604,751, each of which patents is herein incorporated by reference inits entirety, show certain variations of inertia valve mechanisms forcontrolling aspects of compression damping. Additionally, U.S. PublishedPatent Application Nos. 2008/0053768 A1, 2008/0053767 A1, 2008/0035439A1, 2008/0007017 A1, 2007/0296163 A1, 2007/0262555 A1, 2007/0228691 A1,2007/0228690 A1, 2007/0227845 A1, 2007/0227844 A1, 2007/0158927 A1,2007/0119670 A1, 2007/0068751 A1, 2007/0012531 A1, 2006/0065496 A1, eachof which patent applications is herein incorporated by reference in itsentirety, show certain variations of inertia valve mechanisms forcontrolling aspects of compression damping. Optionally, any of theforegoing inertia valve mechanisms or other features may be integrated,or used in combination, with any other features disclosed herein. Ashock absorber or fork may be equipped, for example, with an inertiavalve for controlling an aspect of damping and a position sensitivevalve for controlling another aspect of damping.

FIG. 1 shows an embodiment of a bicycle shock absorber. The shockabsorber includes a body 104 slidably (axially) disposed in a sleeveassembly 102. The sleeve assembly 102 is connected, by helical threads,to an eyelet assembly 106. Eyelet assembly 106 is explained in moredetail in FIG. 10 below. A bearing assembly 108 is connected to an endof the body 104 by threads and is fluid sealed in relation thereto.Inner compression rod 110 is disposed approximately concentricallywithin rebound metering rod 112. Those rods 110 and 112 are disposedapproximately concentrically within shaft 114. Shaft 114 is threaded ata first end in sealing engagement into eyelet (or top cap) 116. Pistonassembly 118 is threaded into a second end of shaft 114 by means ofpiston bolt 120. Floating piston assembly 122 (e.g. “movable barrier”)is disposed within and axially movable in relation to body 104. Thefloating piston assembly 122 divides an interior of body 104 into adamping fluid chamber 124 and a compressible chamber 126. The assemblyof FIG. 1 also forms a spring chamber 128.

In operation an axial compressive force exerted on the shock absorbercauses the body 104 and attached bearing assembly 108 to move axiallyfurther into an interior of the sleeve assembly 102. In so moving, thebody 104 and bearing assembly 108 also move axially relative to thepiston assembly 118, the shaft 114, rods 110 and 112, and the eyeletassembly 106. During that movement, gas in the spring chamber 128 iscompressed thereby storing energy for release during rebound. Dampingoccurs as damping fluid in damping fluid chamber 124 is forced to movefrom a first side 406 (see FIG. 4A) of piston assembly 118 to a secondside 408 (see FIG. 4A) of piston assembly 118 through flow paths,typically through the piston assembly 118, having varying degrees ofdesigned resistance to flow through. The design of a valve pistonassembly, for example, the valve piston assembly 300 of FIG. 3, wheresuch valve piston assembly 300 is an embodiment of a suitable pistonassembly 118, determines the operational fluid flow paths in the pistonassembly 118 through which the damping fluid may flow and therebydictates the degree of damping available. Referring to the embodiment ofFIG. 3, the valve piston assembly 300 is configured so that certainfluid flow paths are open for compression damping and certain other flowpaths are open for rebound damping. That allows for differing degrees ofdamping during shock compression versus shock rebound.

As the body 104 moves further into sleeve assembly 102 duringcompression, shaft 114 enters the volume of damping fluid chamber 124and reduces available fluid volume therein. In one embodiment,compressible chamber 126 is filled with a compressible fluid such as agas. The compressible chamber 126 in one embodiment comprises a gas. Inanother embodiment, the compressible chamber 126 is preloaded at anelevated pressure. Damping fluid chamber 124 is typically filled with aliquid damping fluid that is relatively incompressible. As the shaft 114enters damping fluid chamber 124 and reduces fluid volume therein, therelatively incompressible damping fluid is displaced. The volume ofdamping fluid chamber 124 is therefore correspondingly increased tocompensate for the reduction, due to the incursion of shaft 114, bymovement of floating piston assembly 122 such that the gas in chamber126 is compressed or further compressed. As described herein, floatingpiston assembly 122 separates compressible chamber 126 and damping fluidchamber 124. The floating piston assembly 122 is configured fortransferring pressure from the damping fluid chamber 124 to thecompressible chamber 126. The floating piston assembly 122 moves toreduce the volume of compressible chamber 126 (and compressing the fluidtherein) while increasing (i.e. compensating) the volume of dampingfluid chamber 124.

In one embodiment both compression and rebound damping are selectivelyadjustable by the user. FIG. 2 shows a detail of an embodiment of avalve piston assembly 200 where such valve piston assembly 200 is anembodiment of a suitable piston assembly 118. Referring to FIGS. 1 and2, it is shown that shaft 114 axially abuts damping adjustment spring202 which in turn abuts a shoulder on damping adjustment valve 204.Damping adjustment valve 204 is biased by damping adjustment spring 202to obstruct fluid flow through aperture 206 (in piston bolt 120). Aswill be discussed, shaft 114 is axially and selectively movable towardand away from aperture 206 which in turn increases and decreasesrespectively a seating force of damping adjustment valve 204 in aperture206. During compression, damping fluid in damping fluid chamber 124 mustovercome the seating force of damping adjustment valve 204 in aperture206 in order to flow 420 through aperture 206 and ultimately to thesecond side 408 (of FIG. 4A) of piston assembly 118. The seating forcethereby dictates a first aspect of the compression damping threshold. Inone embodiment, a seating force of the damping adjustment valve 204 maybe externally adjusted by means of the knob 1010 (of FIG. 10) andcorresponding camshaft 1008 (of FIG. 10) with the eyelet cap 106.Rotation of the knob 1010 rotates the camshaft moving shaft 114 axiallyand correspondingly adjusting the closure force (i.e. damping force) ofdamping adjustment valve 204 in aperture 206.

For example, and referring to FIGS. 2 and 4A-E, in one embodiment, asshaft 114 moves towards compressible chamber 124, and inner compressionrod 110 pushes damping adjustment spring 202, damping adjustment spring202 is pushed towards the damping adjustment valve 204. As the pistonassembly 118, including the damping adjustment valve 204 (i.e. the shockabsorber) is compressed, pressure within damping fluid chamber 124increases. This increased pressure pushes against the damping adjustmentvalve 204. If the pressure overcomes a seating force of dampingadjustment valve 204, then aperture 206 opens up and allows dampingfluid to flow through. The damping fluid flows through flow channels 214and 216 (of FIG. 2) to the second side 408 of piston assembly 118.

A second aspect of compression damping is dictated by the compressivepreload of Bellville springs 208 against shuttle 210. Shuttle 210normally blocks flow channel(s) 212, thereby preventing fluid flow froma first side 406 to a second side 408 of piston assembly 118. Bellvillesprings 208 maintain the shuttle 210 in the blocking position untilfluid pressure in damping fluid chamber 124 (below the piston assembly118) exerts a pressure over the area of the flow channel 212 that isgreater than the Bellville Springs 208 preload.

In one embodiment the aforementioned two aspects of controllingcompression damping are independent and their respective functionscontrolled by available respective flow channel 212 and aperture 206 inrelation to the preload on their respective springs, Bellville Spring208 and damping adjustment spring 202, respectively. In one embodimentthe ratio of the area of aperture 212 over the preload on dampingadjustment spring 202 is greater than that same ratio taken for area offlow channel 212 over the preload on Bellville springs 208. That meansthat the same pressure in damping fluid chamber 124 will open theaperture 206 before it will open flow channel 212. Because of that, inuse on a shock absorber equipped bicycle (shock of the embodimentdescribed herein), increased preloads on damping adjustment spring 202will decrease “pedal bob”, the amplitude of which will not typicallycreate a compression velocity (between the body 104 and the sleeve 102)sufficient to elevate pressure in damping fluid chamber 124 to open flowchannel 212. The flow area of aperture 206 is limited however, so ifgreater mass flow is required across piston assembly 118 then ultimatelyaperture 206 will flow choke (e.g. critical flow) and pressure willbegin to increase in damping fluid chamber 124. If a large obstructionis encountered the greater mass flow rate of damping fluid required tobe moved through the piston assembly 118 will (due to amplitude ofobstruction and corresponding amplitude of the compression velocityrequired to accommodate that amplitude which velocity is exhibited asincreased pressure in damping fluid chamber 124) will cause theBellville springs 208 to deflect and thereby allow flow channel 212 toopen.

In one embodiment both of the foregoing damping functions are intrinsicin the design of the valve piston assembly 200. FIG. 3 shows a detail ofthe valve piston assembly 300. In that embodiment the first aspect ofdamping involving aperture 206 and damping adjustment spring 202 is aspreviously described herein. The valve piston assembly 300 of FIG. 3includes another, or “position sensitive” aspect of compression dampingthat operates somewhat differently than (referring to FIG. 2) thepreviously described “second aspect of compression damping.” Of note,the Bellville spring 208 may be used in conjunction with the movablevalve outer 302, to be described in FIG. 3, in order to augment closureforce of the FIG. 3 configuration. FIG. 3 shows piston assembly 118having compression damping flow channel(s) 212 there through. A movablevalve outer 302 selectively obstructs flow channel 212. The movablevalve outer 302 is “nested” approximately concentrically with valveinner 304. A fillable chamber 306 is formed by the engaged movable valveouter 302 and valve inner 304. Optionally the fillable chamber 306contains gas at atmospheric pressure. Additionally, valve shims 318 andspacers 320 may stack out to hold valve inner 304 in contact with pistonassembly 118.

Because of the axially movable floating piston assembly 122, the dampingfluid pressure in damping fluid chamber 124 is maintained at a pressuresubstantially equal to the compressible fluid pressure in compressiblechamber 126 (or vice versa). Because, during compression, the fluidvolume of damping fluid chamber 124 is reduced by intrusion of shaft 114into chamber 124 and the fluid in compressible chamber 126 iscorrespondingly compressed, the pressure of the damping fluid in dampingfluid chamber 124 increases during a compression stroke of the shockabsorber as a function of the axial displacement of the shock absorber.Optionally, the initial (e.g. uncompressed—extended shock) pressurecharge in compressible chamber 126 may be elevated above atmospheric(e.g. 400 psi) and the extended damping fluid pressure of damping fluidchamber 124 will be elevated correspondingly. The result of theforegoing, including the incursion of shaft 114 into damping fluidchamber 124 during compression, is that as the shock absorber strokesfurther in compression the “ambient” pressure of the damping fluid indamping fluid chamber 124 increases. That increase is largelyindependent of any dynamic pressure differential across the pistonassembly 118 due to the velocity of compression. The shock absorber hasan ambient damping fluid pressure that is therefore dependent onposition in the compression stroke of the shock absorber.

In operation a fluid pressure differential, between the damping fluidchamber 124 and the fillable chamber 306, exerts a force, on the engagedpart couple formed by the movable valve outer 302 and valve inner 304,over the annular area defined between the 1^(st) o-ring seal 308 and the2^(nd) o-ring seal 310 of FIG. 3. In one embodiment, gas at atmosphericpressure is contained inside the fillable chamber 306 and damping fluidat an elevated static pressure is contained in damping fluid chamber124. The differential pressure between the damping fluid and thefillable chamber 306 tends to drive the movable valve outer 302 and thevalve inner 304 more tightly together axially in attempt to close gap(s)312. Since the valve inner 304 is initially axially restrained againstthe piston assembly 118 from below and the spring and the shim 318 (or aspring/washer stack) from above, the differential pressure (visually—theclosing of gap 312) causes the movable valve outer 302 to press moretightly against the opening of flow channel 212 which moves the valveinner 304 upward thereby compressing the spring washer stack 322. As gap312 is closed, a greater compression of the spring washer stack 322 isrealized thereby increasing the closure force of movable valve outer 302on flow channel 212. In one embodiment the flow channel 212 may beopened when a fluid pressure below a piston (e.g. in region of fluiddamping chamber 124 of FIG. 1) of the piston assembly 118 is elevatedsufficiently (due to shock absorber compression and dynamic compressionbelow the piston) to overcome the compressed spring washer stack 322above the valve inner 304. In one embodiment, the fillable chamber 306may be externally adjusted. In another embodiment, the fillable chamber306 comprises a fluid. In yet another embodiment, the fillable chamber306 comprises a gas. The gas may be at atmospheric pressure, in oneembodiment. In yet another embodiment, the fillable chamber 306comprises a gas at an elevated pressure, wherein the elevated pressurebiases the variable damper towards an open position.

Referring to FIGS. 4A and 4B, embodiments of valve piston assembly 300or “boost valve” of FIG. 3 is in the process of altering a damping rateof a vehicle suspension damper in accordance with the present technologyis shown. FIG. 4A shows a first damping mechanism 402 comprising a firstsurface 222 and a second surface 224. The first surface 222 abuts thedamping fluid chamber 124. The second surface 224 abuts a dampingadjustment spring 202. FIG. 4A also comprises a second damping mechanism404 that comprises a valve inner 304 and a movable valve outer 302enclosing a fillable chamber 306. First side of piston assembly 118 isreferenced as 406 and second side of piston assembly 118 is referencedas 408. Flow channel 212 runs between first side 406 and second side 408of piston assembly 118. A first flow rate 420 of a fluid is shown asarrows flowing through the damping adjustment valve 204.

According to embodiments of the present technology, the dampingadjustment spring 202 is configured for providing variable resistance topressure from a damping fluid of the damping fluid chamber 124 on thedamping adjustment valve 204 (shown in FIG. 2). The damping adjustmentvalve 204 is configured to open and allow fluid to flow between thedamping fluid chamber 124 and a portion of the vehicle suspension damperthat is sealed off from the damping fluid chamber 124 (e.g., enclosedfillable space 314 [or “a second portion of damping fluid chamber 124”])when a variable first threshold pressure is overcome.

In one embodiment, the fillable space 314 comprises preloaded matter. Inone embodiment, this preloaded matter may be a fluid. In anotherembodiment, this preloaded matter may be a gas.

In embodiments of the present technology, the variable damper comprisesa valve inner 304 that is axially restrained against a piston of thepiston assembly 118. In another embodiment, the variable dampercomprises a movable valve outer 302 configured for selectivelyobstructing a flow channel 212 running between the damping fluid chamber124 and the second side 408 of the piston assembly 118. The second side408 of the piston assembly 118 partially borders an enclosed fillablespace 314. The flow channel 212 is obstructed in response to a stage ofthe compression of the compressible chamber 126.

Referring still to FIG. 4A and during operation of embodiments of thepresent technology, during a compression stroke in accordance with theposition sensitive aspect of compression damping, damping fluid flows502 from a first side 406 of piston assembly 118 to a second side 408 ofpiston assembly 118 through flow channel 212. In doing so and nowreferring to FIG. 4B, the damping fluid exerts a force on the movablevalve outer 302 tending to move movable valve outer 302 off of pistonassembly 118 (and flow channel 212) and to increase gap 312. Of note, inorder to reverse this force and cause the gap 312 to bias towards open,the damping fluid dynamic pressure differential from below the pistonassembly 118 multiplied times the area of the flow channel(s) 212 mustexceed the previously described force that tends to close gap 312.

Referring now to FIG. 4C, an embodiment of a valve piston assembly 300of FIG. 3 in the process of altering a damping rate of a vehiclesuspension damper in accordance with the present technology is shown. Asthe shock absorber compression proceeds in its stroke, the ambientdamping fluid pressure 602 in the fillable enclosed space 314 increases.This ambient damping fluid pressure 602 pushes against the seconddamping mechanism 404 in the direction of the piston assembly 118. Bypushing against the second damping mechanism 404 in this direction, thegap 312 biases towards closed. Therefore, for the position sensitiveaspect of damping to operate, the dynamic fluid pressure differentialacross piston assembly 118 increases as does the correspondingcompression damping coefficient of the shock absorber.

Referring now to FIG. 4D, an embodiment of a valve piston assembly 300of FIG. 3 in the process of altering a damping rate of a vehiclesuspension damper in accordance with the present technology is shown.For example, the threshold of the second damping mechanism 404 isincreased by the increase of the ambient pressure 602 against themovable outer valve 302. The movable outer valve 302 is pushed againstthe piston assembly 118 and the flow channel 212, making it difficultfor damping fluid to flow through flow channel 212 and into the enclosedfillable space 314. The amount of pressure needed to push this dampingfluid through flow channel 212 and past the second damping mechanism 404is increased, thereby having increased the threshold of the seconddamping mechanism 404.

In one embodiment, the first damping mechanism 402 and the seconddamping mechanism 404 utilize at least one common flow channel.

Referring now to FIG. 4E, a valve piston assembly 300 of FIG. 3 with avariable damper spring 606 is shown in accordance with embodiments ofthe present technology. In one, the fillable chamber 306 comprises avariable damper spring 606 having a first end 608 and a second end 610.The first end 608 is restrained by the valve inner 304 and the secondend 610 is restrained by the movable valve outer 302. The variabledamper spring 606 is configured for providing resistance to the variabledamper 404 that is obstructing the flow channel 212 in response to thecompression of the compressible chamber 126. As a result of thisresistance, the variable damper spring 606 biases the variable damper404 towards an open position.

In another embodiment, the variable damper spring 606 is configured tobias the variable damper 404 towards a closed position. In yet anotherembodiment, variable damper spring 606 is positioned such that the firstend 608 and the second end 610 do not engage initially with the initialmovement of movable valve outer 302. However, at some point during thetravel of movable valve outer 302 towards valve inner 304 or away fromvalve inner 304, the first end 608 and the second end 610 engage valveinner 304 and movable valve outer 302, respectively. In one embodiment,once engaged, the variable damper spring 606 biases the movable valveouter 302 towards open. In another embodiment, once engaged, thevariable damper spring 606 biases the movable valve outer 302 towardsclosed.

In one embodiment of the present technology and referring to FIG. 5, avehicle suspension damper 400 comprises at least one damping obstruction412 is shown in accordance with embodiments of the present technology.The damping obstruction 412 is configured to receive an outer portion413 of the movable valve outer 302 when the movable valve outer 302moves in response to a stage of the compression of the compressiblechamber 126. FIG. 5 shows damping obstruction positioned above movablevalve outer 302. In one embodiment, damping obstruction may be one ormore “shims”. In another embodiment, damping obstruction 412 may be oneor more washers.

Referring now to FIG. 6, a damping obstruction 412 touching movablevalve outer 302 is shown in accordance with embodiments of the presenttechnology. It can be seen in FIG. 6 that the damping obstruction 412biases the movable valve outer 302 towards a closed position. In oneembodiment, the damping obstruction 412 is configured for selectedengagement with the movable valve outer 302. For example, the dampingobstruction 412 may be positioned closer to movable valve outer 302 orfurther away from movable valve outer 302, thus enabling a predefinedtiming of engagement. In another embodiment, the damping obstruction 412is externally adjustable.

Referring now to FIG. 7, a damping obstruction 412 is preloaded andtouching movable valve outer 302. For example, FIG. 7 shows movablevalve outer 302 wedged against damping obstruction 412 to such an extentthat damping obstruction 412 is slightly bent towards the movable valveouter 302. This preloaded position also biases the movable valve outer302 towards closed.

In one embodiment, the second damping mechanism 404 is responsive to acompression of the compressible chamber 126, wherein the compressionresults from a selectable input pressure applying pressure. In oneembodiment, input pressure is indirectly caused by compression ofdamping adjustment spring 202. Thus input pressure may be directly orinversely proportional to a stage of compression of the dampingadjustment spring 202.

In one embodiment, the vehicle suspension damper 400 is coupled with anested piston arrangement.

In one embodiment, the vehicle suspension damper 400 comprises anautomatic “blow off” feature. The blow off feature is an automaticoverride permitting the vehicle suspension damper 400 in a “locked out”shock absorber to operate and meter fluid if subjected to a rapid shockevent, like a sudden, abrupt bump in a road.

Optionally, any of the features described herein may be adapted forintegration in to a bicycle or motorcycle fork. For example, FIG. 14through 25, of U.S. Pat. No. 7,273,137 (incorporated herein byreference) show an embodiment of a vehicle suspension fork that may beintegrated with features hereof. Additionally, U.S. Pat. No. 6,592,136,which patent is herein incorporated by reference in its entirety, showsembodiments of a vehicle suspension fork that may be integrated withfeatures hereof. Additionally, Published U.S. Patent Applications2007/0119672 A1 and 2007/0007743 A1, each of which applications isherein incorporated by reference in its entirety, show embodiments of avehicle suspension fork that may be integrated with features hereof.

FIG. 8A shows a fork damping cartridge that would, in one embodiment,comprise the internal workings of at least one leg of a bicycle fork (ormotorcycle fork). The fork damping cartridge is, for example, compatiblewith a Fox 36 or 40 series trail fork. FIGS. 8H, 8I and 8J are furtherperspective views of a base valve assembly and the components therein.Although the cartridge may function inside a single legged fork or shockabsorber, in one embodiment the cartridge is installed inside onetelescoping leg of a two legged vehicle (e.g. bicycle) fork (see FIG.8B, described below). The top cap 802 includes male threads and an outerdiameter o-ring seal. The top cap 802 is threaded into sealingengagement with an inner diameter of an upper fork tube (that extendsthrough a crown, both not shown). The top cap 802 anchors the upper endof the cartridge axially to the upper end of the upper fork tube. Thelower end of the cartridge includes a shaft 820 and a nut assembly 818threaded onto the shaft 820. In one embodiment, the shaft 820 extendsthrough a hole in the bottom of a lower fork tube (not shown) such thatthe cartridge is substantially inside a combination of the lower forktube and an upper fork tube (not shown) telescopically engagedtherewith. The nut assembly 818 is threaded onto the shaft 820 fromoutside of the lower fork tube and the cartridge is thereby anchoredaxially to the bottom of the lower fork tube.

The top cap 802 is connected to piston rod 894 which in turn isconnected to piston assembly 118. The top cap 802 carries adjuster knob806, which is connected to adjuster plug 808. The adjuster plug 808axially abuts adjustment shaft 810 which in turn axially abuts needlebody 812. Needle body 812 includes needle 814 which is disposed invariable axial relation within orifice 816 of the piston assembly 118.The nut assembly 818 is connected to shaft 820, which, through lowerdamper 822 internal parts, is connected to lower damper body 824 whichis in turn connected to damper body 826. Although adjuster knob 806,adjuster plug 808, adjustment shaft 810, needle body 812 and needle 804are axially movable relative to top cap 802, piston rod 894, pistonassembly 118 and orifice 816, all of those move together axially intelescopic relation to damper body 826.

During operation, the damper leg of the fork is subject to compressionand rebound loads. The compression is induced by disparities in theterrain being traversed by a vehicle equipped with the fork. The reboundis induced by a spring (e.g. gas spring, mechanical spring, coil—notshown), preferably located in another leg of the fork, which storesenergy during compression of the fork and then releases that energy whenthe disparity is passed. The energy is released in urging the suspensionunit to elongate axially following the axial compression during whichthe energy is stored. The top cap 802 and its connected parts (asdisclosed herein) move with the upper fork tube during compression andrebound and the nut assembly 818 and its connected parts (as disclosedherein) move with the lower fork tube.

Movement of the upper fork tube (not shown) relative to the lower forktube (not shown) causes piston assembly 118 to move axially within thedamper body 826. During a compression stoke the piston assembly 118moves downward in the damper body 826 and thereby reduces the volume ofcompressible chamber 828. As fluid is displaced from the compressiblechamber 828, some of it flows through passages and deflects the one wayshim valve to enter the rebound chamber 830. Some of the displaced fluidflows through orifice 816 into the reservoir 822. The resistance tomovement of fluid from the compressible chamber 828, through thepassages (and shim valve on piston) and orifice 816 provide compressiondamping for the suspension unit in which the damper cartridge isincluded.

During a rebound stoke the piston assembly 118 moves upward in thedamper body 826 and thereby increases the volume of compressible chamber828. As fluid is displaced from the rebound chamber 830, it flowsthrough apertures and into an annular volume. It then flows past needle814, through channels and orifice 816 to enter the compressible chamber828. Also, the previously displaced fluid flows through orifice 816 fromthe reservoir 822 and back into the compressible chamber 828. Theresistance to movement of fluid from the rebound chamber 830, throughthe channels and orifice 816 provide rebound damping for the suspensionunit in which the damper cartridge is included.

As an alternative to or augmentation of an internal floating piston,annular bladder 836 (e.g. “flexible bladder”) is located withinreservoir 822 and provides a compensation chamber for the volume ofshaft 820 as it enters compressible chamber 828 during compression. Theannular bladder 836 comprises an elastic material or structure, forexample an elastomeric toroid or semi-toroid or a metallic or plasticbellows or any other suitable structure or material. An interior ofannular bladder 836 is charged with a compressible fluid at an initialpressure. Optionally, the annular bladder 836 may remain at atmosphericpressure as is described elsewhere herein. As shaft 820 enterscompressible chamber 828 during compression, fluid flows fromcompressible chamber 828 into reservoir 822 and the volume of annularbladder 836 is reduced correspondingly as the gas within annular bladder836 is compressed. Such gas compression correspondingly raises theambient pressure within the compressible chamber 828 and rebound chamber830.

In one embodiment, the annular bladder 836 acts as the floating pistonassembly 122 of FIG. 1. In one embodiment, the annular bladder 836 maybe pressurized from a source outside of the fork. Additionally, in oneembodiment of a vehicle suspension damper 400 in a leg of a fork, thevariable damper is coupled with a piston assembly 118. In anotherembodiment, the variable damper is coupled with a ported bulkhead.

According to one embodiment, valve piston assembly 300 of FIG. 3(including a valve assembly and a piston assembly) is placed on theshaft 114 to integrate with the assembly of FIG. 8A. Optionally, theadjustment body 812 of FIG. 8A may be used in conjunction with thepiston assembly 300 of FIG. 3 or the entire piston assembly 300 of FIG.3 may be used in the fork of FIG. 8A, including the damping adjustmentvalve 204 in aperture 206 of FIG. 2. In operation, the valve pistonassembly 300 increasingly restricts flow through flow channel(s) 212 asthe gas compression in annular bladder 836 raises the ambient pressurewithin compressible chamber 828 and rebound chamber 830 during acompression stroke. Of note, in one embodiment the piston assembly inthe fork is replaced by the boost valve type piston assembly.

Referring now to FIG. 8B, a two legged vehicle (e.g. bicycle) fork 840comprising a vehicle suspension damper is shown in accordance withembodiments of the present technology. For example, and as describedherein, the cartridge of FIG. 8A may be installed in one leg of fork840. In one embodiment and as shown in FIG. 8B and as described herein,one leg 800 may include the vehicle suspension damper 400 and the otherleg 845 of fork 840 may include a spring (e.g. gas spring, mechanicalspring, coil—not shown), which stores energy during compression of thefork and then releases that energy when a disparity is passed. In oneembodiment, the spring is adjustable.

In one embodiment, forks 800 and 840 comprise boost valves. In anotherembodiment, forks 800 and 840 comprise pressurized boost valves. Forexample, areas within forks 800 and 840 that are capable of holdingmatter may be “pressurized” from an outside source with air, gas, and/orliquid.

Referring now to FIG. 8C, a cross-sectional view of a vehicle suspensiondamper and related components within a leg of a two legged fork is shownin accordance with embodiments of the present technology. The annularbladder 836 within reservoir 822 can be clearly seen. Of note, theannular bladder 836 is coupled with the top end and the variable dampercoupled with the upper bulkhead 850.

In one embodiment, as shown in FIG. 8F, the boost valve pair (movablevalve outer 870 and valve inner 871, is mounted in a control assembly891 of a vehicle fork 890. The control assembly 891 is shown in greaterdetail in FIGS. 8E and 8F. Referring to FIG. 8D, the fork 890 includesan upper tube 892 telescopically received within a lower tube 893 andaxially slidable relative thereto. The lower tube 893 includes a pistonrod 894 having a damping valve adjustment shaft 895 disposed coaxiallytherein and axially and rotationally movable relative thereto. Thedamping valve adjustment shaft 895 moves axially in response to rotationof the damping adjustment knob 858 and thereby adjusts the interferenceof needle valve 889 within a damping orifice that extends through thecenter of the damping piston 898. The damping valve adjustment knob 896is fixed to the lower end of the damping valve adjustment shaft 895where the damping valve adjustment knob 896 is accessible from anexterior of the fork and in one embodiment is suited for manipulation byhand thereby allowing manual adjustment of the mechanical damping valve897. The damping valve adjustment knob 896 is threaded through the lowerend of the lower tube 893. When the damping valve adjustment knob 896 isselectively rotated by a user, a shaft of the damping valve adjustmentknob 896 moves axially in proportion to the thread helix and the shaftpushes or pulls on the damping valve adjustment shaft 895. The dampingpiston 898 (e.g. orifices there through) controls the flow of fluid fromthe compression side of compression chamber 861 of the damping fluidchamber to the rebound chamber 899 of the damping fluid chamber during acompression of the fork 853 and vice versa during an extension of thefork 890 thereby providing a selectable damping resistance. Optionally,a spring (not shown) is included between the damping valve adjustmentshaft 895 and the needle valve 889 so that during compression of thefork 890, a threshold pressure in compression chamber 861 can overcomethe preset or selected spring force (based on adjustment of the dampingvalve adjustment knob 896), thereby allowing the fork 890 to “blow off”or allow damping fluid to flow through (to rebound chamber 899) anotherwise substantially closed piston orifice. The damping piston 898may also comprise a variable damper (boost valve) such as that shown anddescribed herein for example in FIG. 4A.

During compression of the fork, the damping valve adjustment shaft 895progresses into the compression/rebound chamber 861/899 and as it doesit must, because the compression/rebound chamber 861/899 is of fixedvolume, displace a volume of fluid (typically “incompressible” dampingliquid such as hydraulic oil) corresponding to the volume of the dampingvalve adjustment shaft 895 as it enters the compression/rebound chamber861/899. The displacement of damping fluid from the compression/reboundchamber 861/899 affords an additional damping feature. Referring also toFIGS. 8E and 8F, the displaced fluid flows from compression chamber 861into chamber 863. From there it continues into throat 950 to orifice865. When the damping fluid pressure at orifice 865 is sufficient toovercome the metering valve 952 preload spring 867, the damping fluidflows through orifice 865 and along flow paths 868 (through a pluralityof apertures 888 disposed circumferentially about the throat 950 body)into a plurality of boost valve orifices 869. The plurality of boostvalve orifices 869 are obstructed at a lower end by movable valve outer870. The movable valve outer 870 is “nested” with the valve inner 871and an annular fluid chamber 872 is formed between the movable valveouter 870 and the valve inner 871. In one embodiment the annular fluidchamber 872 is filled by gas at atmospheric pressure. When the static or“ambient” pressure of the damping fluid is greater than atmospheric, itacts to force the movable valve outer 870 upwardly and the valve inner871 downwardly. In other words, movable valve outer 870 and valve inner871 tend to become more tightly “nested.” That in turn forces movablevalve outer 870 against the plurality of boost valve orifices 869. Thegreater the differential pressure between the damping fluid and theannular fluid chamber 875, the greater the force will be that is exertedby the movable valve outer 870 against the plurality of boost valveorifices 869. That in turn will increase resistance to damping fluidflow through the plurality of boost valve orifices 869 toward flow path873 and will thereby increase the compressive damping force of the fork853. Damping fluid flowing through flow path 873 and flow path 874 thenflows into the annular fluid chamber 875 where its pressure may beaffected by gas pressure in annular chamber 876.

In one embodiment the annular fluid chamber 872 (or 306 of FIG. 3,referred to as a “fillable chamber”) is filled with substantiallynothing and therefore contains a vacuum. That may be accomplished byengaging or “nesting” the movable valve outer 870 and the valve inner871 in a vacuum or by pumping the annular fluid chamber 872 down throughan orifice (not shown) and then plugging the orifice. When annular fluidchamber 872 is at vacuum, mere atmospheric pressure will be higher. Inone embodiment pressurization of the shock absorber or fork leg (e.g.through gas induction valve 877 into annular chamber 876) may beatmospheric or slightly above atmospheric. In one low pressureembodiment the annular bladder 880 or floating piston 122 (of FIG. 1) isdesirable in order to isolate a minimized volume of gas for facilitatingpressure increases during a compression stroke of the suspension. In oneembodiment the annular fluid chamber 872 serves to isolate the gascompensation chamber from the damping fluid thereby avoiding anyintermingling of the gas and the fluid (e.g. liquid oil) which wouldresult in a reduced damping performance (due to the damping fluidbecoming emulsified).

In one embodiment the annular fluid chamber 872 (or 306 of FIG. 3,fillable chamber) is filled with gas at above atmospheric pressurewhereby such gas pressure is specified to be greater than an initial(corresponding to an extended state of the suspension) static dampingfluid pressure and corresponding gas pressure within annular chamber 876(or 126 of FIG. 1, referred to as a “compensation chamber”). In such anembodiment the gas in annular fluid chamber 872 (or 306 of FIG. 3,fillable chamber) biases the movable outer valve and the valve inner 870(302 of FIG. 3) and 871 (304 of FIG. 3) away from one another (e.g.increasing gap 312 of FIG. 3) until the suspension is strokedsufficiently in compression to raise the static damping fluid pressureto a value higher than that annular fluid chamber 872 (306 of FIG. 3,fillable chamber) gas pressure. In one embodiment the boost valvedamping mechanism is held open until a predetermined point in thecompression stroke is reached. In such embodiment the suspensionexhibits very compliant damping characteristics until later in thecompression stroke at which point the suspension becomes more rigid (andin that way suspension “bottom out” may be mitigated). In one embodimenta mechanical spring is placed within the annular fluid chamber 872 (306of FIG. 3, fillable chamber) such that it is in compression between themovable valve outer 870 and valve inner 871 halves and biases them tomove apart in a manner, and with a result, similar to the foregoingdescription (except that the spring rate may be more linear than aninitial gas pressure charge “spring”).

In one embodiment the volume of annular chamber 876 (or 126 of FIG. 1,compensation chamber) is configured in proportion to the diameter ofdamping valve adjustment shaft 895 (114 of FIG. 1, referred to as“shaft”) and the length of the suspension stroke or the length of thedamping valve adjustment shaft 895 (114 of FIG. 1, shaft) that will, atmost, enter into compensation/rebound chamber 861/899 (or 124 of FIG. 1,referred to as “damping fluid chamber”). Such a consideration may bereferred to as the “damper compression ratio.” In one embodiment thevolume of the annular chamber 876 (126 of FIG. 1, compensation chamber)is twice the volume of the piston rod 894 (114 of FIG. 1, shaft) thatmay enter the compression/rebound chamber 861/899 (124 of FIG. 1,damping fluid chamber) at maximum compression stroke of the suspensionor in other words the damper compression ratio is two ([volume of thecompensating chamber] divided by the [shaft volume maximum minus shaftvolume [in the damping chamber] initial]). In some boost valvesuspension embodiments, useful compression ratios range from 1.5 to 4.In some embodiments more particular useful compression ratios range from2 to 3. In some fork embodiments, compression ratios may be relativelylower in a range because a fork typically operates within a vehiclesystem on a one to one basis (i.e. the wheel moves an inch and the forkmoves an inch whereas a shock may move ½ inch per 2 inch of wheel travelthereby increasing the inch per inch resistance required of an effectiveshock: there is no levering linkage usually associated with a fork wherethere is often linkage associated with a rear shock).

The static or ambient pressure of the damping fluid may be altered bypressurizing (in one embodiment with a compressible fluid such as a gas)the piston shaft compensation chamber. In one embodiment compensationchamber is pressurized by adding gas, at a desired damping fluid ambientpressure, through gas induction valve 877. Gas induction valve 877 maybe a rubber plug under a set screw, a Schrader type gas valve, a Prestatype gas valve or any valve suitable for gas introduction and sealing atpressure. When the gas is introduced into gas induction valve 877, itflows through orifices 878 and into annular chamber 876. In oneembodiment annular chamber 876 is sealed at a lower end by an annularpartition 879 and sealed in order to limit the volume of pressurized gasinfluencing the dimension of the upper tube 892 (if the upper tube 892is completely pressurized dimensional changes and possible bindingbetween fork legs may occur).

The pressurized gas acts almost without resistance on the damping fluidthrough annular bladder 880. In one embodiment the annular bladder 880is made from an elastomer (or other suitable flexible material) and actsas a pressure transmitting diaphragm (annular) between the gas inannular chamber 876 and the damping fluid in annular bladder interior875. Because the damping fluid in annular bladder interior 875 is inpressure communication with the entire damping fluid system includingcompression/rebound chamber 861/899, communication of gas pressure inannular chamber 876 to fluid pressure in annular bladder interior 875(through annular bladder 880) increases the ambient damping fluidpressure to that of the gas pressure of chamber 881. As describedherein, that ambient pressure influences the damping force exerted byboost valve or valves included within the fork (e.g. 870/871). As thefork 853 compresses during a compression stroke, the volume of dampingfluid displaced by damping valve adjustment shaft 895 acts to furtherincrease the ambient damping fluid pressure in the system by compressingthe gas in chamber 881 by an amount corresponding to the damping valveadjustment shaft 895 introduced into compression/rebound chamber861/899.

In one embodiment, the vehicle fork 890 includes an adjustable dampingmechanism comprising a metering valve 952. That metering valve 952 canbe adjusted by rotation of top cap 882 which correspondingly rotatesadjuster 883. The shaft of adjuster 883 is non round and engages asimilarly non round hole though nut 884. When adjuster 883 is rotated,the nut 884 is rotated and also traverses its threaded housing axially.As the nut 884 moves axially, the preload on spring 885 iscorrespondingly altered. Because the spring 885 exerts an axial load onthe metering valve 952, the damping characteristic, or resistance toflow though orifice 865 is selectively and manually adjusted by turningtop cap 882.

In one embodiment the annular bladder 880 may be constructed fromextruded or pulltruded (or other suitable continuous tube formingoperation or method) tube stock cut in segments to suitable length. Suchmanufacturing option may reduce costs per bladder and increase thebladder material and property options available. In one embodiment thebladder may be so constructed by virtue of the mechanism employed hereinto create a fluid tight seal at each end of the bladder. As shown inFIGS. 8E and 8F, bladder end 886 is upset and the upset end is capturedby seal ring 887. During installation, seal ring 887 is pressed into theinner diameter at an end of annular bladder 880 such that it straddlesthe upset bladder end 886. The bladder end 886, with seal ring 887installed is then slid axially into an inner diameter of a solidcylindrical housing, such as for example the inner diameter of annularpartition 879 (or at an upper end, a “control assembly housing” (notnumbered but shown). The solid housing (e.g. 879) and seal ring 887 aredimensioned such the annular space formed between them is radiallythinner than the thickness of the upset bladder end 886 thereby placingthe elastic upset in a sealing squeeze (such as an o-ring mechanismwould function).

In one embodiment the bladder stock may be extruded from a suitableelastic material and then cut to appropriate length. The lengths maythen be upset by a secondary upsetting process (e.g. using heat andpressure). Optionally the upsetting is not necessary and the seal ring887 and inner diameter of the annular partition 879 are designed tosqueeze, in sealing engagement, the mere thickness of the bladder stockwhere such squeeze is also sufficient to resist axially loading and“shrinkage” forces that may occur when the bladder is internallypressurized (to expand radially).

Referring now to FIG. 8G, are cross sectional views of a vehiclesuspension damper and related components within a fork 852 configuredfor a motorcycle is shown in accordance with embodiments of the presenttechnology. Shown in fork 852 are the following components: pistonassembly 853, variable damper 854, movable outer valve 855, reverse bendshim 856, main stack of shims 857, the first big diameter shim 858furthest from the piston assembly 853, IFP chamber 860 (similar infunction to the damping fluid chamber 124 of FIGS. 1-7, compressionbleed adjuster 862, spring pre-load adjuster 864 and IFP spring 866.

In operation, the variable damper 854 acts against a reverse bend shim856 arrangement. As the pressure in the IFP chamber 860 increases due tocompression of the fork 852, the movable outer valve 855 pushes againstthe first big diameter shim 858 furthest from the piston assembly 853.The first big diameter shim 858 bends against the main stack of shims857, effectively increasing the stiffness of the main stack of shims 857as the fork 852 is compressed.

At the beginning of travel, when the pressure of the IFP chamber 860 isat a minimum, the variable damper 854 is not influencing the dampingforce. At some point into the travel, when the reverse bend shim 856assembly starts to engage the stack, is when the variable damper 854starts acting. This gives initial free movement of the fork 852 and thenproduces the position-sensitive effect to the compression damping deeperin travel.

Of note, external adjustments may be made to the components of fork 852.For example, a compression bleed adjuster 862 is coupled in parallelwith variable damper 854. The compression bleed adjuster 862 isconfigurable to be adjusted externally. In addition, in one embodiment,there is a spring pre-load adjuster 864 which acts to change thepre-load on the IFP spring 866. In one embodiment, turning the springpre-load adjuster 864 clockwise will increase the pre-load on the IFPspring 866 and make the variable damper 854 react closer to the initialpart of its travel. Turning the spring pre-load adjuster 864 willcontrol the dive or pitch of the fork 852 (most notable in the corners).

Another external adjustment that may be made in accordance withembodiments of the present technology is to alter the height of theexternal oil bath. Raising the oil height will increase the ramping ofthe air volume in the fork 852, thus increasing the apparent pressure ofthe IFP chamber 860. Most likely, this adjustment will affect the lastfew inches of travel.

Embodiments in accordance with the present technology may be describedas follows. In one embodiment, a vehicle suspension fork comprises adamping fluid chamber having a variable volume; a reservoir chamber influid communication with the damping fluid chamber; a flow restrictiondisposed in a flow path between the damping fluid chamber and thereservoir chamber; and a compressible chamber separated from thereservoir chamber by a flexible bladder.

Furthermore, in one embodiment, the flexible bladder (annular bladder)comprises an elastic material.

In another embodiment, the fork described herein comprises a first outertube and a second outer tube telescopically disposed within the firstouter tube. Furthermore, in another embodiment, the fork comprising afirst outer tube and a second outer tube described above may comprise apair of first outer tubes disposed respectively within a pair of secondouter tubes.

In another embodiment, the bladder of the fork is substantially tubularin form. The bladder may be sealingly retained at one end with a solidsurround imposing a squeeze on the bladder end. Additionally, thebladder may be retained at both ends by such squeeze.

In another embodiment, the fork comprises a damping compression ratiofalling within a range of 1.8 to 3.2.

In one embodiment the vehicle suspension comprises a damping fluidchamber having a reservoir portion; a compressible chamber; a first gasspring chamber; a second gas spring chamber; a damping piston shaft; adamping valve having a variable flow orifice responsive a movement ofthe shaft within the damping fluid chamber; and a gas spring valvecommunicating gas between the first and second gas spring chambers inresponse to a change of position of the shaft within the damping fluidchamber. The vehicle suspension damper comprises a first dampingmechanism and the second damping mechanism utilizes at least one commonflow channel. In another embodiment, the pressure within the fillablechamber of the vehicle suspension damper may be externally adjusted. Inyet another embodiment, a space within said fillable chamber of thevehicle suspension damper is selected from a group consisting of avacuum, a gas, and a gas at atmospheric pressure. In another embodiment,a space within said fillable chamber of the vehicle suspension dampercomprises a gas at an elevated pressure, the elevated pressure biasingthe variable damper towards an open position.

In one embodiment, the at least one damping obstruction of the vehiclesuspension damper is configured for selected engagement with the movablevalve outer. In another embodiment, the at least one damping obstructionof the vehicle suspension damper is externally adjustable. In anotherembodiment, the damping obstruction may be a washer.

In one embodiment, the movable barrier of the vehicle suspension dampercomprises a piston. In another embodiment, the movable barrier comprisesa flexible bladder. In one embodiment, the compressible chamber ispreloaded at an elevated pressure. In another embodiment, the content ofthe compressible chamber is externally adjustable.

In one embodiment, the enclosed fillable space comprises preloadedmatter. In another embodiment, the movable barrier comprises a flexiblediaphragm. In yet another embodiment, the preloaded matter is a gas. Inyet another embodiment, the rebound spring is externally adjustable.

In one embodiment, the second damping mechanism of the vehiclesuspension damper is responsive to a pressure compression of thecompressible chamber, wherein the pressure results from a selectableinput pressure communicated with the compressible chamber. In yetanother embodiment, the selectable input pressure is an accumulator. Theselectable input pressure may be a pump in one embodiment. In oneembodiment, the vehicle suspension damper is coupled with a nestedpiston arrangement.

Referring to FIG. 9, a flow chart 900 of an example method for alteringa damping rate of a vehicle suspension damper 400 in accordance withembodiments of the present technology is shown. In one embodiment and asdescribed herein, method 900 comprises flowing 905 a first flow rate 412of a damping fluid through a first damping mechanism 402.

Referring now to 910 of FIG. 9 and as described herein, a volume ofcompressible is compressed through a portion of a stroke of a piston ofthe vehicle suspension damper 400. Referring to 915 of FIG. 9 and asdescribed herein, a flow rate requirement is increased beyond athreshold of a second damping mechanism 404.

Now referring to 920 of FIG. 9 and as described herein, an ambientpressure of a damping fluid is increased in proportion to thecompression of 910. Furthermore, referring to 925 in FIG. 9 and asdescribed herein, the threshold of the second damping mechanism 404 isincreased.

Referring to FIG. 10, a blown-up schematic of an eyelet assembly 106 inaccordance with embodiments of the present technology is shown. In oneembodiment, eyelet assembly 106 includes, but is not limited to, eyelet1002, cam shaft with 3 lobes 1004, compression spring 1006, cam in a 3×2position 1008, rebound or “RD” adjust knob 1010 (in one embodimentadjusts rebound damping independently of compression damping),compression adjust lever boss 1012, lever 1014, compression adjust knob1016, air valve assembly 1018, and cap air valve 1020.

In one embodiment, eyelet assembly 1000 and the components therein worktogether to enable the adjustment of internal components of the vehiclesuspension damper 400, thereby adjusting mechanically (andindependently) either or both of the compression damping and rebounddamping rates.

FIGS. 11A and 11B are schematics of an example cam 1008 of FIG. 10, inaccordance with embodiments of the present technology. FIGS. 11A and 11Bshows side view 1102 of cam 1008 with a first portion 1104 and a secondportion 1106. FIGS. 11A and 11B also shows a frontal view 1105 of firstportion 1104. In one embodiment, first portion 1104 includes lobeswithin. For example frontal view 1105 shows lobes 1108, 1110 and 1112.However, it is understood that more or less lobes may be present inembodiments of the present technology. Rotation of these lobes,resulting from rotation of the corresponding adjuster knobs 806 and camshafts 1004 causes these lobes 1108, 1110 and 1112, working in tandemwith the piston rods 110 and rebound metering rods 112 to cause axialdisplacement thereof and correspondingly altering spring compression inselected damping valves to adjust damping rates.

Referring now to FIGS. 12A-D, are schematics of different views of anexample RD adjust knob 1010 in accordance with embodiments of thepresent technology. For example 1202 of FIGS. 12A-D shows a side view ofRD adjust knob 1010 (as seen in FIG. 10) showing components 1204 and1206 that couple with cam 1008. 1208 of FIGS. 12A-D shows a side view ofRD adjust knob 1010 that emphasizes, via the line area A-A, a structuralaspect including a gap 1209 configured for receiving another component.Frontal, sectional view 1210 of the line area A-A shows a hole 1211through the approximate center of RD adjust knob 1010 and the gap's 1209interaction with that hole 1211. Referring still to FIGS. 12A-D, 1212shows a rotated side view of the RD adjust knob 1010 in a position thatis different from side view 1208. Rotation of the adjustment knob 1010causes rotation of the camshaft 1008 and corresponding axial movement(referring to FIG. 1) of shaft 114. Axial movement of shaft 114increases or decreases preload on rebound shim valve stack (notnumbered) that obstructs rebound damping fluid flow orifices through thepiston. When preload is decreased for example, rebound damping fluidflows more freely from above the piston to below the piston duringsuspension extension and therefore the suspension extends more rapidly.

FIG. 13 shows a cut away view of a shock absorber and its correspondinginternal parts. In one embodiment the damper body 1 is hollow andcontains a floating piston 10 moveably disposed therein. The floatingpiston 10 divides the interior of the damper body 1 into a compensatorgas chamber 9 arid a compression damping fluid chamber 12. Thecompensator gas chamber 9 volume is reduced, by downward movement of thefloating piston 10, in proportion to the volume of the damper supportshaft 20 that enters the rebound damping fluid chamber 21 as the damperbody 1 moves telescopically into the air sleeve 2 during the compressionof the shock absorber. As the damper body 1 moves telescopically intothe air sleeve 2, pushing the gas compression piston 15 correspondinglyfurther upward in the air sleeve 2, the volume of the primary gas springchamber 14 is reduced, thereby compressing or further compressing, thegas in the primary gas spring chamber 14.

In one embodiment, the gas pressure in the primary gas spring chamber 14continues to increase until the top of the gas compression piston 15impinges upon the lower end of the communication valve shaft 19. At thatpoint the force exerted by the gas compression piston 15 on the lowerend of the communication valve shaft 19 moves the communication valvemember 17 off of the communication valve seat 18 thereby opening a fluidflow path through the valve assembly 18 and between the primary gasspring chamber 14 and the secondary gas volume chamber 16. Two things(at least) occur as a result of the fluid communication between theprimary 14 and secondary 16 gas chambers. Any pressure differentialbetween the primary 14 and secondary 16 chambers equalizes once the flowpath 18 between them is opened. Additionally, the effective volume ofthe shock absorber gas spring is increased by the amount of thesecondary chamber 16.

There are several shock absorber parameters that can be varied in orderto derive a preferred travel versus pressure profile, or “spring rate”over the range of travel. Variables that may be selectively alteredinclude: length and diameter of the primary chamber 14, volume of thesecondary chamber 16, initial pressure state of the primary chamber 14,initial pressure state of the secondary chamber 16 and length of thecommunication valve shaft 19.

The initial pressure state and the diameter of the primary 14 chamberdefine the shape of the travel versus spring pressure profile for theshock absorber prior to opening the communication valve 17. Preferablythe values chosen for those variables result in a substantially linearspring rate prior to fluid communication between the primary 14 andsecondary chambers 16. In one embodiment, the initial pressure in thesecondary chamber 16 is set to equal a pre-calculated pressure in theprimary chamber 14 corresponding to a point just before the gascompression piston 15 contacts the lower end of the communication valveshaft 19. When the communication valve 17 is opened with such secondarychamber 16 pressure setting, there is no significant differentialpressure between the primary 14 and secondary 16 chambers. Further,there is no significant system pressure drop When the primary 14 andsecondary 16 chambers are fluidly communicated. The gas spring volume isincreased by the amount of the secondary chamber 16 and the spring rateis correspondingly decreased but the transition from the spring rateassociated with only the primary chamber 14 to the spring rateassociated with the combined primary 14 and secondary 16 chambers isrelatively smooth.

Alternatively the initial pressure in the secondary chamber 16 may beset at the same time as the initial pressure in the primary chamber 14and at the same pressure. During an initial compression of the shockabsorber the volume of the primary chamber 14 is reduced and thepressure in the primary chamber 14 rises until the communication valve17 is opened. Because the secondary chamber 16 pressure is still at itsinitial pressure setting fluid flows from the primary chamber 14,through the communication valve 18 into the secondary chamber 16 whenthe communication valve 17 is opened. The pressure in the now combinedprimary 14 and secondary 16 chambers equalizes at a pressure valuebetween the pre-communication primary chamber 14 pressure and theinitial secondary chamber 16 pressure. During subsequent compressioncycles of the shock absorber, the secondary chamber 16 retains thecompression pressure of the primary chamber 14 as a set point and nofurther equalization occurs upon opening the communication valve 17.When the communication valve 17 is opened, there may be a large massflow rate of gas through the communication valve 17. Such flow may causethe communication valve 17 to open further at high velocities.Uncontrolled opening velocity may damage the communication valve 17 orsurrounding parts within the shock absorber. In one embodiment thesealing head of communication valve 17 is large enough to provide alarge flow area upon initial cracking open of the communication valve17. Such larger flow area will result in lower flow velocities and lesslikelihood of flow driving the valve head and stem to damaging impact.In one embodiment the sealing portion of “head” of the communicationvalve 17 is at least two times as large in diameter as the shaft of thecommunication valve 17. In one embodiment the ratio for the sealing headdiameter to the shaft diameter is 1.3 to 4.

In one embodiment a pressure regulator or “pressure divider”, asillustrated in FIGS. 14a and 14b , may be used in lieu of, or incombination with, the communication valve 17 to facilitate furtherselective tailoring of the spring rate curve. Such a pressure dividermay be used in parallel or in series with a communication valve 17. Thepressure divider may be disposed in the present system to maintain aknown differential pressure between the primary and secondary chambersupon opening of the communication valve 17. Optionally the shaft 19actuated communication valve 17 may be replaced by, or used in parallelwith, a spring loaded pressure relief valve (not shown) or othersuitable pressure relief valve. Such a pressure relief valve may be setto limit the differential pressure that may build between the primaryand secondary chambers during operation. Optionally the pressure dividermay be placed downstream of the fill valve 3 in order to regulatepressure in one or both of the primary 14 and secondary chambers 16.Optionally one or more pressure dividers may be used in lieu of the fillvalve 3 to regulate the pressure in either or both of the primary 14 andsecondary chambers 16 in relation to atmospheric pressure or anadditional pressure reservoir. The pressure divider is shown having a2:1 area ratio. It is noted that any suitable ratio may be used (byproviding suitably sized piston areas) in order to facilitate themaintenance of desired differential pressures. It is also noteworthythat, while no vent hole is shown, or absolutely necessary, the“air@atmospheric” volume shown in the FIGS. 14A and 14B represent avolume that may be vented to atmosphere or other suitable ambientpressure (in one embodiment, by a vent hole not shown). In someinstances, such as where the pressure divider is included inside theshock absorber between chambers, it may be preferable to leave the“air@atmospheric” volume closed. Minor variances in that volume pressurewill have only negligible effect on the operation of the pressuredivider.

In one embodiment, as shown in FIG. 13, the communication valve 17 andshaft 19 are not generally coaxial with the shock absorber. That allowsthe damper support shaft 20 to be occupied by control mechanisms forselectively adjusting and/or blocking valves or orifices of the damperassembly 11 to effect changes in damping rates or lock-out of the damperaltogether. Further, such non-coaxial placement of the communicationvalve 17 and shaft 19 allows separation of the damping fluid (e.g. oil)from the spring fluid (e.g. pressurized gas) thereby reducing thepossibility of damping fade (i.e. intermingling of gas and liquidreduces the effectiveness of the liquid as a damping medium) duringextended periods of use. As such, shock absorbers of the present typemay include isolated gas charge or internal floating piston type dampingsystems.

It may be desirable to select the point in the travel at which theprimary 14 and secondary 16 chambers are communicated. In one embodimentthe valve member 17/communication valve shaft 19 is available indifferent lengths where a longer length is installed for communicationearlier in the shock stroke and a shorter length is installed forcommunication later in the shock stroke. Optionally, the flow splittermodule 35 is axially movable within the shock absorber so that thedistance between the top of the gas compression piston 15 and the bottomof the communication valve shaft 19 can be selectively varied. The flowsplitter 35, and correspondingly the valve 17 and shaft 19, can bepositioned closer to the gas compression piston 15 for communicationearlier in the shock stroke or further from the gas compression piston15 for communication later in the shock stroke. In one embodiment (notshown in detail) the flow splitter 35 is axial movable by manipulationof the gas fill valve assembly 3 upwardly or downwardly in a lengthwise(axial relative to the shock) slot opened in a wall of the lank 6. Asuitable retainer plate partially covering the slot is used to retainthe gas fill valve assembly 3 and correspondingly the flow splittermodule 35 in the selected axial position relative to the tank 6 andcorrespondingly relative to the top of the gas compression piston 15.

In one embodiment the primary 14 and secondary 16 chambers are filled byintroducing pressure, from a suitable gas pump or other source ofpressurized gas, into the gas fill valve 3. In one embodiment the gasfill valve 3 comprises a Schrader type valve. Alternatively, the gasfill valve may comprise any other suitable fill valve mechanism. ASchrader type gas fill valve assembly 3 is shown in FIG. 15. The fillvalve body 34 is installed in the flow splitter module 35, which in turnis installed in the shock absorber tank 6; generally between the primary14 and secondary 16 chambers so that gas introduced into the valve 3 canreadily and selectively be distributed to one or both of the primary 14and secondary 16 chambers.

Referring to FIG. 15, the primary fill valve core 23 may be a Schradertype valve core. In such an embodiment, the valve stem 22 is axiallyfixed relative to, or abutted to, the primary fill valve 24 andcorresponding valve pusher stem 25. The secondary chamber fill valvestem 33 is axially adjacent the valve pusher stem 25. The secondarychamber fill valve 30 is located at or proximate an end of the secondarychamber fill valve stem 33.

FIG. 16 shows a Schrader type fill valve module. The Schrader typemodule has fewer components than the modified Schrader valve (e.g. thanFIG. 15). Tolerances are therefore less critical and part costs arethereby reduced. The module includes a fill valve body 34. The primaryvalve core 23, pusher stem/secondary chamber fill valve stem 25/33 andsecondary chamber fill valve 30 are integrated into a single unitdisposed within the fill valve body 34. The integrated unit functionsmuch as the separate piece assembly (described below) functions with anexception being that there is no gap 26. There are fewer parts and fewercritical manufacturing tolerances for the integrated unit.

Referring to FIG. 15, the fill valve 3 is designed to fill both of theprimary 14 and secondary 16 chambers with pressurized gas from thesingle valve body 34. In one aspect the valve stem 22 is connected,through the valve core 23 to the primary fill valve 24 such that axialmovement of the valve stem 22 causes axial movement of the primary fillvalve 24 and valve pusher stem 25. Sufficient axial movement of thevalve pusher stem 25 closes the gap 26 until the valve pusher stem 25contacts the secondary chamber fill valve stem 33. Following suchclosure of the gap 26, further movement of the valve pusher stem 25moves the secondary chamber fill valve stem 33 and correspondinglyseparates the secondary chamber fill valve 30 from the secondary chamberfill valve seat 31. The result is that sufficient axial movement of thevalve stem 22 opens the primary fill Valve 24 and further movement ofthe valve stem 22 subsequently opens the secondary chamber fill valve30.

The valve stem 22 may be moved either mechanically, by a probe on apressure fitting of a pressurized gas source, or solely by theintroduction of pressurized gas into the fill valve body 34 wherein thepressurized gas acts over the surface area (i.e. piston area) of theprimary fill valve 24. In one embodiment, the dimension of the gap 26 isset such that movement of the valve stem 22 and primary fill valve 24,caused solely by the introduction of pressure, is not sufficient undernormal operating pressures to close the gap 26 between the valve pusherstem 25 and the secondary chamber fill valve stem 33. Correspondingly,only the primary fill valve is opened and pressurized gas is onlyintroduced through the annulus 27 and primary passage 32 into theprimary chamber 14.

Optionally, a mechanical probe, attached to a pressure hose fitting forexample, is used to move the valve stem 22. The length of the probe issufficient to open the primary fill valve 24, close the gap 26, causemovement of the valve pusher stem 25 and secondary chamber fill valvestem 33 and thereby open the secondary chamber fill valve 30.Correspondingly, pressurized gas flows into the primary chamber aspreviously described and also through the open secondary chamber fillvalve 30, through the secondary passage 29 and into the secondarychamber 16.

The fill valve and shock absorber shown in the Figures herein includeo-ring seals as shown and where appropriate. Any suitable seals may beused and seals may be used where not shown or omitted even though shownin any case as appropriate for the channelling and retention ofpressurized fluids.

While the foregoing is directed to embodiments of the present invention,other and further embodiments of the invention may be implementedwithout departing from the scope of the invention, and the scope thereofis determined by the claims that follow.

What we claim is:
 1. A vehicle suspension damper for providing avariable damping rate, said vehicle suspension damper comprising: adamping fluid chamber, said damping fluid chamber having a first portionand a second portion; a damping fluid disposed in said damping fluidchamber; a damping fluid flow path between said first portion of saiddamping fluid chamber and said second portion of said damping fluidchamber; a first damping mechanism fluidically coupled to said dampingfluid flow path, said first damping mechanism affecting flow of saiddamping fluid through said damping fluid flow path, said first dampingmechanism comprising: an aperture fluidically coupled to said dampingfluid flow path; and a damping adjustment valve coupled to said apertureto control flow of said damping fluid through said aperture, saiddamping adjustment valve adjustable external to said damping fluidchamber: a second damping mechanism fluidically coupled to at least aportion of said damping fluid flow path such that said first dampingmechanism and said second damping mechanism both affect flow of saiddamping fluid through a common portion of said damping fluid flow path,said second damping mechanism affecting flow of said damping fluidthrough said at least a portion of said damping fluid flow path, saidsecond damping mechanism comprising: a variable damper enclosing afillable chamber, said variable damper comprising: a valve inner; and amovable valve outer to engage portions of said valve inner, saidfillable chamber creates a gap between said valve inner and said movablevalve outer such that said valve inner and said movable valve outerenclose said fillable chamber, and such that fluid does not flow out ofsaid fillable chamber, said movable valve outer selectively obstructssaid second flow path in response to a state of a compression of saidvehicle suspension damper, said fillable chamber having a fillablechamber pressure introduced therein during assembly of said variabledamper; a shaft movably disposed within said damping fluid chamber, saidshaft movable into said damping fluid chamber during a compressionstroke of said vehicle suspension damper, during which time adifferential pressure between said damping fluid and said fillablechamber drives said movable valve outer and said valve inner moretightly together axially, to cause said second damping mechanism toincrease a restriction of flow of said damping fluid through said atleast a portion of said damping fluid flow path, and create an increasein compressive damping force for said vehicle suspension damper; and acompressible chamber, wherein upon said compression of said vehiclesuspension damper, said shaft enters said first fluid chamber todisplace and reduce an available fluid volume, whereby a combination ofan incursion of said shaft and said damping fluid remaining in saidfirst fluid chamber compresses a compressible chamber and increases thevolume of said first fluid chamber, a pressure and volume of saidcompressible chamber being in a compressed or further compressed statesuch that a static pressure of said damping fluid is increasedfunctionally with change of a position in a compression stroke of saidvehicle suspension damper.
 2. The vehicle suspension damper of claim 1,wherein said fillable chamber pressure is typical atmospheric pressure.3. The vehicle suspension damper of claim 1, wherein said fillablechamber pressure is greater than typical atmospheric pressure.
 4. Thevehicle suspension damper of claim 1, wherein said fillable chamberpressure is less than typical atmospheric pressure.
 5. The vehiclesuspension damper of claim 1, wherein said fillable chamber is evacuatedand sealed to maintain a vacuum in said fillable chamber.
 6. The vehiclesuspension damper of claim 1, further comprising: at least one dampingobstruction coupled with said valve inner, said at least one dampingobstruction to receive an outer portion of said movable valve outer inresponse to said state of said compression of said compressible chamber,said at least one damping obstruction biasing said movable valve outertowards a closed position.
 7. The vehicle suspension damper of claim 1,further comprising: a movable barrier to transfer pressure between saidfirst fluid chamber and said compressible chamber.
 8. The vehiclesuspension damper of claim 1, wherein a seating force of said moveablevalve outer is adjusted by manipulation of an exterior portion of saidvehicle suspension damper.
 9. The vehicle suspension damper of claim 1,wherein said fillable chamber comprises: a variable damper spring havinga first end and a second end, said first end restrained by said valveinner, said second end restrained by said movable valve outer, saidvariable damper spring to provide resistance to said variable damperobstructing said second flow path in response to said compression ofsaid compressible chamber, said variable damper spring biasing saidvariable damper towards an open position.
 10. The vehicle suspensiondamper of claim 1, wherein said vehicle suspension damper is positionedin a first leg of a fork of a vehicle.
 11. The vehicle suspension damperof claim 6, further comprising: a rebound spring, said rebound springpositioned in a second leg of said fork to induce a rebound of said forkby storing energy during compression of said fork and releasing saidenergy when a disparity is passed.
 12. The vehicle suspension damper ofclaim 1, further comprising: a flexible bladder positioned within areservoir in pressure communication with said first fluid chamber, saidflexible bladder deflects proportionally to an amount of fluid flowingbetween said first fluid chamber and said second fluid chamber.
 13. Thevehicle suspension damper of claim 1, wherein said second dampingmechanism is coupled with a piston assembly.
 14. A vehicle suspensiondamper for providing a variable damping rate, said vehicle suspensiondamper comprising: a damping fluid chamber, said damping fluid chamberhaving a first portion and a second portion; a damping fluid disposed insaid damping fluid chamber; a damping fluid flow path between said firstportion of said damping fluid chamber and said second portion of saiddamping fluid chamber; a first damping mechanism fluidically coupled tosaid damping fluid flow path, said first damping mechanism affectingflow of said damping fluid through said damping fluid flow path, saidfirst damping mechanism comprising: an aperture fluidically coupled tosaid damping fluid flow path; and a damping adjustment valve coupled tosaid aperture to control flow of said damping fluid through saidaperture, said damping adjustment valve adjustable external to saiddamping fluid chamber: a second damping mechanism fluidically coupled toat least a portion of said damping fluid flow path such that said firstdamping mechanism and said second damping mechanism both affect flow ofsaid damping fluid through a common portion of said damping fluid flowpath, said second damping mechanism affecting flow of said damping fluidthrough said at least a portion of said damping fluid flow path, saidsecond damping mechanism comprising: a variable damper enclosing afillable chamber, said variable damper comprising: a valve inner; and amovable valve outer to engage portions of said valve inner, saidfillable chamber creates a gap between said valve inner and said movablevalve outer such that said valve inner and said movable valve outerenclose said fillable chamber, and such that fluid does not flow out ofsaid fillable chamber, said movable valve outer selectively obstructssaid second flow path in response to a state of a compression of saidvehicle suspension damper, said fillable chamber having a springdisposed therein to bias movement between said valve inner and saidmovable valve outer; a shaft movably disposed within said damping fluidchamber, said shaft movable into said damping fluid chamber during acompression stroke of said vehicle suspension damper, during which timea differential pressure between said damping fluid and said fillablechamber drives said movable valve outer and said valve inner moretightly together axially, to cause said second damping mechanism toincrease a restriction of flow of said damping fluid through said atleast a portion of said damping fluid flow path, and create an increasein compressive damping force for said vehicle suspension damper; and acompressible chamber, wherein upon said compression of said vehiclesuspension damper, said shaft enters said first fluid chamber todisplace and reduce an available fluid volume, whereby a combination ofan incursion of said shaft and said damping fluid remaining in saidfirst fluid chamber compresses a compressible chamber and increases thevolume of said first fluid chamber, a pressure and volume of saidcompressible chamber being in a compressed or further compressed statesuch that a static pressure of said damping fluid is increasedfunctionally with change of a position in a compression stroke of saidvehicle suspension damper.
 15. The vehicle suspension damper of claim14, wherein said spring is a mechanical spring.
 16. The vehiclesuspension damper of claim 14, wherein said spring is in compressionwithin said fillable chamber to bias said valve inner and said movablevalve outer away from each other.
 17. The vehicle suspension damper ofclaim 14, further comprising: at least one damping obstruction coupledwith said valve inner, said at least one damping obstruction to receivean outer portion of said movable valve outer in response to said stateof said compression of said compressible chamber, said at least onedamping obstruction biasing said movable valve outer towards a closedposition.
 18. The vehicle suspension damper of claim 14, furthercomprising: a movable barrier to transfer pressure between said firstfluid chamber and said compressible chamber.
 19. The vehicle suspensiondamper of claim 14, wherein a seating force of said moveable valve outeris adjusted by manipulation of an exterior portion of said vehiclesuspension damper.
 20. The vehicle suspension damper of claim 14,further comprising: a flexible bladder positioned within a reservoir inpressure communication with said first fluid chamber, said flexiblebladder deflects proportionally to an amount of fluid flowing betweensaid first fluid chamber and said second fluid chamber.